Distributed process control systems, like those used in chemical, petroleum or other processes, typically include one or more process controllers communicatively coupled to one or more field devices via analog, digital or combined analog/digital buses. The field devices, which may be, for example, valves, valve positioners, switches and transmitters (e.g., temperature, pressure, level and flow rate sensors), are located within the process environment and perform process functions such as opening or closing valves, measuring process parameters, etc. Smart field devices, such as the field devices conforming to the well known Fieldbus protocol may also perform control calculations, alarming functions, and other control functions commonly implemented within the controller. The process controllers, which are also typically located within the plant environment, receive signals indicative of process measurements made by the field devices and/or other information pertaining to the field devices and execute a controller application that runs, for example, different control modules which make process control decisions, generate control signals based on the received information and coordinate with the control modules or blocks being performed in the field devices, such as HART and Fieldbus field devices. The control modules in the controller send the control signals over the communication lines to the field devices to thereby control the operation of the process plant.
Information from the field devices and the controller is usually made available over a data highway to one or more other hardware devices, such as operator workstations, personal computers, data historians, report generators, centralized databases, etc., typically placed in control rooms or other locations away from the harsher plant environment. These hardware devices run applications that may, for example, enable an operator to perform functions with respect to the process, such as changing settings of the process control routine, modifying the operation of the control modules within the controllers or the field devices, viewing the current state of the process, viewing alarms generated by field devices and controllers, simulating the operation of the process for the purpose of training personnel or testing the process control software, keeping and updating a configuration database, etc.
As an example, the DeltaV™ control system, sold by Fisher Rosemount Systems, Inc. includes multiple applications stored within and executed by different devices located at diverse places within a process plant. A configuration application, which resides in one or more operator workstations, enables users to create or change process control modules and download these process control modules via a data highway to dedicated distributed controllers. Typically, these control modules are made up of communicatively interconnected function blocks, which are objects in an object oriented programming protocol that perform functions within the control scheme based on inputs thereto and that provide outputs to other function blocks within the control scheme. The configuration application may also allow a configuration designer to create or change operator interfaces which are used by a viewing application to display data to an operator and to enable the operator to change settings, such as set points, within the process control routines. Each dedicated controller and, in some cases, field devices, stores and executes a controller application that runs the control modules assigned and downloaded thereto to implement actual process control functionality. The viewing applications, which may be run on one or more operator workstations, receive data from the controller application via the data highway and display this data to process control system designers, operators, or users using the user interfaces, and may provide any of a number of different views, such as an operator's view, an engineer's view, a technician's view, etc. A data historian application is typically stored in and executed by a data historian device that collects and stores some or all of the data provided across the data highway while a configuration database application may run in a still further computer attached to the data highway to store the current process control routine configuration and data associated therewith. Alternatively, the configuration database may be located in the same workstation as the configuration application.
Presently, configuration applications may include a library of template objects, such as function block template objects and, in some cases, control module template objects. These configuration applications are used to configure a control strategy for a process plant. The template objects all have default properties, settings and methods associated therewith and the engineer using the configuration application can select these template objects and essentially place copies of the selected template objects into a configuration screen to develop a control module. During the process of selecting and placing the template objects into the configuration screen, the engineer interconnects the inputs and outputs of these objects and changes their parameters, names, tags and other properties to create a specific control module for a specific use in the process plant. After creating one or more such control modules, the engineer can then instantiate the control module and download it to the appropriate controller or controllers and field devices for execution during operation of the process plant.
Thereafter, the engineer generally creates one or more displays for operators, maintenance personnel, etc. within the process plant by selecting and building display objects in a display creation application. These displays are typically implemented on a system wide basis in one or more of the workstations and provide preconfigured displays to the operator or maintenance persons regarding the operating state of the control system or the devices within the plant. Typically, these displays take the form of alarming displays that receive and display alarms generated by controllers or devices within the process plant, control displays indicating the operating state of the controllers and other devices within the process plant, maintenance displays indicating the functioning state of the devices within the process plant, etc. These displays are generally preconfigured to display, in known manners, information or data received from the process control modules or the devices within the process plant. In some known systems, displays are created through the use of objects that have a graphic associated with a physical or logical element and that is communicatively tied to the physical or logical element to receive data about the physical or logical element. The object may change the graphic on the display screen based on the received data to illustrate, for example, that a tank is half full, to illustrate the flow measured by a flow sensor, etc.
Similar to the control configuration application, a display creation application has template graphical display items, such as tanks, valves, sensors, operator control buttons like slide bars, on/off switches, etc. which may be placed on a screen in any desired configuration to create an operator display, maintenance display and the like. When placed onto the screen, individual graphic items may be interconnected on the screen in a manner that provides some information or display of the inner-workings of the process plant to different users. However, to animate the graphic display, the display creator must manually tie each of the graphical items to data generated within the process plant, such as data measured by sensors or indicative of valve positions, etc. by specifying a communication link between the graphic item and the relevant data source within the process plant. This process is tedious, time consuming and may be fraught with error.
While the control template objects within the control configuration application and the display items within the display creation application are convenient because they can be copied and used to create many different control modules and graphical displays, there is often a need to create numerous of the same control module and graphical display for different equipment within the process plant. For example, many medium to large sized process plants have numerous instances of the same or similar equipment that can be controlled and viewed using the same basic general control module and display. To create these numerous control modules and displays, however, a general control module or display module is created and this general control or display module is then copied for each of the different pieces of equipment for which it is applicable. Of course, after being copied, each of the new control or display modules must be manually altered in the configuration application to specify the particular equipment to which it is attached and all of these control and display modules must then be instantiated and downloaded to the process control system.
Unfortunately, the control modules and displays items discussed above are not modular in any manner. Thus, after being copied, each of the control modules and displays must be manually and individually altered using the appropriate configuration application to specify the equipment within the plant to which they are to be associated. In a plant having many copies of the same type of equipment (i.e., replicated equipment), this process is tedious, time consuming and fraught with operator introduced errors. Still further, once programmed, these different control modules and displays are not aware of each other. Therefore, to make a change to the control modules once created, the engineer or operator must manually make the same change to each of the different control modules for the different replicated equipment which, again, is time consuming and tedious. The same problem applies for the graphical views created for the different sets of replicated equipment within the plant. In other words, once a specific control module or a specific graphical view is created (individually or by being copied from a template object) and is then tied to a particular set of equipment within the plant, this control module or graphical view exists as a separate entity or object within the system without any automatic awareness of the other control modules or graphical displays that are the same or similar to it. As a result, changes applicable to every one of the control modules and graphical displays of a particular type must be made individually on those modules and displays.
Still further, because each control module and display is an individual object, it must be open, in the sense that all of its internal parameters, views, function blocks, and other elements must be made available to any user to be changed, viewed, etc. Currently, there is no manner of controlling what certain operators or other users may see or have access to in these control modules and displays and, thus, there is no ability to hide certain elements of these control modules and displays, such as proprietary software and methods, alarming activities, etc. from the user of the control modules and displays.